Recently the use of enzymes, especially of microbial origin, has been more and more common. Enzymes are used in several industries including, for example, the starch industry, the dairy industry and the detergent industry. It is well known in the detergent industry that the use of enzymes, particularly proteolytic enzymes, has created industrial hygiene concerns for detergent factory workers, particularly due to the health risks associated with dustiness of the available enzymes.
Since the introduction of enzymes into the detergent business, many developments in the granulation and coating of enzymes to reduce enzyme dust have been offered by the industry. However, in today's state of ever-increasing environmental concern and heightened awareness of industrial hygiene, there remains a continuing need for low dust enzyme granules. Furthermore, there are additional characteristics desirable in enzyme granules not currently available in known granulation products. Some of these additional characteristics are related to the need to further alleviate industrial hygiene concerns (lower dust granules) while optimizing customer and end-user satisfaction (oxidatively stable and low residue granules) with the product while simultaneously reducing the cost of granulation (improved processing time), thus reducing cost of the overall enzyme product.
Depending on the desired end use of the granule, desirable characteristics may include the need for delayed release of the enzyme, preferably without having to increase the amount of chlorine scavenger additives currently used in granulation techniques. This delayed release has potential benefit, for example, in protecting enzymes from oxidation or autolytic degradation in washing machines until sufficient amounts of stabilizing proteins or peptides are released from dirty clothing into the wash water. Conversely, if the granule is to be used in an automatic dishwashing detergent (ADD), it would be desirable to have quick dissolution of the granule with no residue or film-forming properties on the surface of the dish or glassware in the dishwasher. Additional desirable characteristics include low residue granule formulations (where low residue is defined as a reduced tendency to leave noticeable undissolved residues or filming on clothes or other material such as glassware or plates, etc.). This characteristic is desirable to the customer (end-user) of a detergent or ADD formulation. In addition, improved stability (enhanced shelf life) formulations are needed in the industry. Accomplishing all these desired characteristics simultaneously while maintaining cost containment for the granule production is a particularly challenging task. For example, many potential polymers to delay the release of the enzyme leave behind insoluble residues, which are undesirable to the user, or such polymers cause increased processing time, which causes increased costs. Also, most potential granulating cores, which are attrition-resistant and therefore suitable for producing low dust granules, tend to leave behind insoluble residues.
Therefore, it is an object of the present invention to provide low dust, low residue enzyme granules. These granules preferably have increased stability. It is another object of the present invention to provide processes and enzyme granule compositions which afford the formation of such improved granules in much lower processing time, thus reducing cost of the granular product.